Effects of opioid-free anaesthesia on postoperative nausea and vomiting in patients undergoing video-assisted thoracoscopic surgery (OFA-PONV trial): study protocol for a randomised controlled trial

Abstract Background Postoperative nausea and vomiting (PONV) is a common complication after general anaesthesia and is associated with morbidity and prolonged length of stay. Growing evidence suggest that opioid-free general anaesthesia (OFA) may reduce PONV in various surgical settings. We aim to evaluate the efficacy of OFA on the incidence of PONV compared with opioid-based anaesthesia among adults undergoing thoracoscopic surgery. Methods This is a prospective, single-centre, randomised controlled trial comparing OFA and opioid-based anaesthesia for thoracoscopic surgery. A total of 168 adults will be randomised with a 1:1 ratio to receive either opioid-free anaesthesia or opioid-based anaesthesia. The primary outcome will be the incidence of PONV within 24 h after operation. The secondary outcomes will include the severity of PONV, quality of recovery, pain at rest, 6-min walking test, and health-related quality of life after operation. Discussion The benefit-risk of OFA for patients after operation is contradictory in previous studies, so further study is required. This trial will focus on the effect of OFA on the incidence of PONV in patients undergoing thoracoscopic surgery. This trial adopts uniformed PONV and perioperative pain management, standardised randomised and blind, clear-cut inclusion and exclusion criteria, and standardised scales to assess the severity of PONV after surgery, the quality of postoperative recovery, and the health status at 6 months. The findings of this study will help to provide references to promote early recovery of patients after lung surgery. Trial registration ClinicalTrials.gov NCT05411159. Registered on 9 June 2022.